The IOSMOS project: a multi-disciplinary approach for Ionian sea water quality monitoring.

The coastal marine environment is a complex and dynamic ecosystem, strongly subject to environmental degradation, because of both natural and anthropogenic causes. In the last years several remote sensing-based approaches for coastal water monitoring and investigation have been proposed. Among the few satellite packages useful for these purposes, the Moderate-Resolution Imaging Spectroradiometer (MODIS), aboard the Earth Observing System (EOS) Terra (since 2000) and Aqua (since 2002) satellites is one of the most used. It is the only one, still operational, that assures a long historical series of data with a good trade-off between spatial and temporal resolution, as well as an adequate spectral resolution in the visible portion of the electromagnetic spectrum. One of the main limit of the MODIS-based Ocean Color (OC) products is their low sensitivity to the retrieved parameters in shallow waters, where the signal at the sensor is influenced also by bottom reflectance. To overcome these limits, as well as to better identify the actual sea water status for a specific region of the interest, in this work we implemented the Robust Satellite Techniques (RST) approach on long-term (i.e. ten years) historical series of MODIS OC products. In detail, the parameters investigated by RST was the Chlorophyll-a (Chl-a) concentration, while the region of interest was the Ionian sea water off the coast of Basilicata region (southern Italy), in the Gulf of Taranto. Achieved results shown in this paper confirm that RST, analyzing the historical behavior of the signal at pixel level, is capable to detect long term trend of the investigated parameter as well as its medium/short temporal changes, allowing for a recognition of the most exposed areas as well as for a timely identification of any possible critical situation.